Optical polarization

About: Optical polarization is a research topic. Over the lifetime, 13992 publications have been published within this topic receiving 244284 citations.

Effects of focusing on third-order nonlinear processes in isotropic media. [laser beam interactions

Abstract: A theoretical analysis of third-order nonlinear interactions of focused laser beams is performed for the processes \omega_{1} + \omega_{2} + \omega_{3} \rightarrow \omega_{4}, \omega_{1} + \omega_{2} - \omega_{3} \rightarrow \omega_{4} , and \omega_{1} - \omega_{2} - \omega_{3} \rightarrow \omega_{4} . The total power and far-field beam profile of the generated radiation is related to the total powers of the fundamental beams, to the tightness and location of the focus, and to the value of the difference between the wave vectors of the generated radiation and driving polarization. The optimum degree of wave-vector mismatch as a function of tightness and location of focus is determined for each of the three processes. The process \omega_{1} + \omega_{2} - \omega_{3} \rightarrow \omega_{4} is found to be unique in that it is always optimized by focusing as tightly as possible. Experimental results, which verify the theory for the processes \omega_{1} + \omega_{2} + \omega_{3} \rightarrow \omega_{4} and \omega_{1} + \omega_{2} - \omega_{3} \rightarrow \omega_{4} , are presented.

Polarized light

Abstract: With the development of practical polarizing sheets, polarized light, long known and employed by science, is being given increasingly wide use in engineering and industry. Its applications in the study of stresses, in photography, stereoscopic motion pictures, vehicle lighting, and display lighting, are among those mentioned by this author, who reviews polarized light for the engineer.

Kramers-Kronig relations in nonlinear optics

Abstract: We review dispersion relations, which relate the real part of the optical susceptibility (refraction) to the imaginary part (absorption). We derive and discuss these relations as applied to nonlinear optical systems. It is shown that in the nonlinear case, for self-action effects the correct form for such dispersion relations is nondegenerate, i.e. it is necessary to use multiple frequency arguments. Nonlinear dispersion relations have been shown to be very useful as they usually only require integration over a limited frequency range (corresponding to frequencies at which the absorption changes), unlike the conventional linear Kramers-Kronig relation which requires integration over all absorbing frequencies. Furthermore, calculation of refractive index changes using dispersion relations is easier than a direct calculation of the susceptibility, as transition rates (which give absorption coefficients) are, in general, far easier to calculate than the expectation value of the optical polarization. Both resonant (generation of some excitation that is long lived compared with an optical period) and nonresonant ‘instantaneous’ optical nonlinearities are discussed, and it is shown that the nonlinear dispersion relation has a common form and can be understood in terms of the linear Kramers-Kronig relation applied to a new system consisting of the material plus some ‘perturbation’. We present several examples of the form of this external perturbation, which can be viewed as the pump in a pump-probe experiment. We discuss the two-level saturated atom model and bandfilling in semiconductors among others for the resonant case. For the nonresonant case some recent work is included where the electronic nonlinear refractive coefficient,n2, is determined from the nonlinear absorption processes of two-photon absorption, Raman transitions and the a.c. Stark effect. We also review how the dispersion relations can be extended to give alternative forms for frequency summation which, for example, allows the real and imaginary parts ofχ(2) to be related.

Spin-orbit interaction of a photon in an inhomogeneous medium

Abstract: As light propagates in an optically inhomogeneous medium, bending and twisting of the beam cause the rotation of the polarization plane. This is the well-known Rytov-Vladimirsky effect or Berry phase. Considering this effect as the result of an interaction between the spin of the photon (polarization) and its orbital motion, one can expect the reverse effect. In fact, the additional angular shift of a trajectory of the circularly polarized beam (CPB) was recently studied for the particular case of an optical fiber. In this paper the spin-orbit interaction Hamiltonian is obtained both in geometrical optics and in wave optics. We have calculated also the effect of the transverse shift of CPB under refraction on the boundary of two media. The expressions for the angular shift of a trajectory of CPB in optical fibers with two types of refractive-index profiles have been obtained. Geometrical optics expressions can be applied for the typical waveguides only at lengths less than 0.05 cm. However, using the geometric optical picture we can successfully describe statistical properties of speckle patterns of laser radiation as it propagates at a considerable distance.